Incadescent lamp.



G. F. HEUSTIS.

INCANDESCENT LAMP. APPLICATION FILED was 22, 1914.

1,1 86,986. Patented June 13, 1916.

GEORGE F. HEUSTIS, OF MALDEN, MASSACHUSETTS.

INCANDESCENT LAMP.

Specification of Letters Patent. Patented J une 13, 1916.

Application filed June 22, 1914. Serial No. 846,421.

'1 b all whom it may concern Be it known that I, Gconon F. Hnusrrs, a citizen of the United States, residing at Maiden, in the county of Middlesex and State of Massachusetts, have invented an Improvement in Incandescent Lamps, of which the following is a specification.

It has been the universal practice, in the operation of incandescent lamps in series, to provide the fixture, or socket, by which the lamp is supported, with a fusible resistance, which is normally interposed between two conductors, yieldingly actuated to move into contact and respectively connected to the fixture terminals, so that the current will normally pass through the filament of the lamp, but which will fuse immediately, when the filament breaks, and permit said conductors to come into contact, and cut-out the filament from the circuit, so that the circuit will not be broken.

Prior to my invention it has been customary to provide the fusible resistance in the lamp socket between terminal springs which act to hold the socket in the fixture, the-arrangement being such that when the fusible resistance is to be renewed, the socket must be withdrawn from the base, and, as the reflector is frequently arranged on the socket, in such a position that the latter cannot be conveniently removed, except by pulling on the lamp, which is held therein, the result is that the lamp is frequently broken, or the bulb is wrenched from its stem.

The objects of my invention are to incorporate in an incandescent lamp, a simple and effective means for completing the circuit when the filament breaks, so that the necessity of employing such means in the fixture may be avoided, and the renewal of the fusible resistance may be accomplished by merely renewing the lamp, and so to arrange such means that said resistance may be readily renewed, in case it becomes fused and the lamp is otherwise intact, and further, to apply such means to the type of lamp now in general use without materially increasing its cost of manufacture. I accomplish these objects by providing the stem of a lamp of ordinary construction with cut-out conductors, which are electrically connected to the lamp or terminals, and are arranged so that one conductor will engage the central socket terminal, when the lamp is screwed into the socket, and will be yieldingly engaged by the other conductor, which is normally held out of contact therewith by a fusible resistance.

F or a more complete understanding of my invention, reference is made to the accompanying drawing, in which,

Figure 1 is a central, vertical sectional view of an incandescent lamp embodying my invention. Fig. 2 is a similar View, showing certain parts in different positions. Figs. 3, 4 and 5 are, respectively, side, plan and end elevations, on an enlarged scale of the lamp stem.

In the drawings, the incandescent lamp 772- is shown as supported in a common form of socket c, the spring terminals d, of which, while usually separated by a fusible resist-* ance, are, in the present instance, separated by a non-fusible resistance, or insulator Said terminals d are respectively connected, one to the socket cut-out spring 70, and the other to the screw-threaded terminal 9, into which the lamp stem at is screwed, said outout spring is being arranged to engage a lug g on the terminal 9, when the lamp is removed from the socket.

According to my invention, I provide the lamp stem with a rigid U-shaped metal arm 37, one end of which is provided with a plate 0 mounted on the end of the lamp stem, and connected to one end of the filament and the other end of which is provided with a simi lar plate p, which is held in position parallel to the plate 0, and at a short distance therefrom, both plates being held in planes at right angles to the longitudinal central line of the lamp stem.

A cut-out spring 8 is mounted on the end of the lamp neck and is soldered to, or formed integrally with the side electrode a, said spring extending between the two plates 0 and p, and being actuated to bear against the outer plate 10. Said spring is normally held out of electrical contact with plate 7) by means of a fusible resistance disk 1' commonly termed film cut-out.

With the above described construction, when the lamp is screwed into the socket, plate p will engage the arm is and move it out of contact with the lug 9, so that the current will pass through the lamp filament in the ordinary manner. In case, however, the filament breaks, then the resistance 1 will be fused and the spring 8 will be moved into contact with the plate p, cutting out the filament and restoring the lamp cir? cuit.

lL-ul It will be obvious that it will be merely necessary, vvhen supplying a nevv lamp, to remove the old one from the socket and screw another in place, avoiding the necessity of removing the socket from the lamp base and renewing the usual fusible resistance betvveen the terminal springs, and, in case the disk r should be fused by an overload, the spring may be readily pressed dovvn and a new dish inserted.

will be apparent that the above described construction may be incorporated in a ordinary lamp with but slight addition to the cost ot manutacture.

I claim 1. in incandescent lamp haring its stem provided with middle and side terminals, a conductor extend 1g from each of said terminals, one of said conductors having a contact plate transverse y disposed beyond the stem to provide an outer face, arranged to engage socket terminal, and an inner face, and means to hold the other of said conductors and said inner face in yielding engagement, to permit the interposition of a fusible resistance.

2'. in incandescent lamp having its stem )rovided vcith a middle and a side terminal, a U-shaped conductor, having one leg connected to said middle terminal, the other leg having a transversely disposed contact plate at its end arranged to engage a socket terminal at its outer side, and a cut-out spring connected to said side terminal at one end, and arranged to engage the inner side of said contact plate at its other end and having a. i'usible resistance interposed therebetween.

3. An incandescent lamp having its stem provided With a middle terminal fixed on the end of said stem and a side terminal, a

(Ionics of this patent may be obtained for rigid conductor connected to said middle terminal, extending beyond said stem and having a contact plate at its end arranged approximately parallel to the end of said stem at a distance therefrom and in position to engage a socket-terminal at its outer side, a cut-out spring mounted on the end of said stenrin electrical contact with said side terminal and actuated to engage the in nor side of said plate, and a fusible resistance interposed between said spring and said plate.

in incandescent lamp having its stein prmided with middle and side terminals, a conductor extending from each ot' said terminals, one of said conductors having a contact plate transversely disposed beyond the stem to provide an outer face, arranged to en age a socket terminal, and an inner face, and means to hold the other oi said conduc tors and said inner face in such a relation ship as to permit the interposition and engagement of a lihn cut-out with both.

5. An electric lamp having a lateral threaded contacting shell and a center terminal provided with a U-sha )ed contacting clip, the lateral shell being provided with an integral portion extending Within the contacting clip of the center terminal, and means permitting the passage of current from the center terminal clip to the extension of the lateral shell when the lamp circuit is interrupted.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing vvitnesses.

GEORGE F. HEUSTIS.

lVitnesses H. B. DAVIS, L. H. HARRIMAN.

Washington, 1). $5." 

